This invention relates to the field of cosmetics and more specifically to nail polish remover products in which the chemical stability and efficacy of alkylene carbonate-containing products are improved and to such products that comply with new government regulations by utilizing low vapor pressure volatile organic compounds (LVP-VOCs). The invention relates, furthermore, to alkylene carbonate-containing general cleaners such as paint remover (or stripper) products with improved stability and efficacy.
For reasons of economy and efficacy, the most common solvent systems utilized for removing nail polishes (also known as nail lacquers) have been acetone and ethyl acetate. However, many problems including skin irritation and skin and cuticle desiccation are associated with the use of these solvents at high concentrations, and many remedies have been described for these problems (See, Curtis (U.S. Pat. No. 4,485,037), Hofmann (U.S. Pat. No. 4,824,662), Hofmann (U.S. Pat. No. 5,077,038), Helioff et al. (U.S. Pat. No. 5,024,779), Remz et al. (U.S. Pat. No. 5,294,435), Miner et al. (U.S. Pat. No. 5,342,536) and Faryniarz et al. (U.S. Pat. No. 5,486,305)).
Solvent systems other than acetone and ethyl acetate have been described in the patent literature for nail lacquer removers, but these have met with limited commercial success. Many of these alternative systems have distinct drawbacks, including health risks and environmental toxicity problems (See, Adams (U.S. Pat. No. 4,543,206), Dotolo et al. (U.S. Pat. No. 5,346,652) and Bayless (U.S. Pat. No. 5,372,742)).
Thickening or gelling systems for enhancing nail polish lacquer removers have also been suggested (See, Minton et al. (U.S. Pat. No. 4,197,212), Day (U.S. Pat. No. 4,804,486) and Miner (U.S. Pat. No. 5,543,085)).
Acetone and methyl acetate (but not ethyl acetate) are currently considered by the California Air Resource Board (CARB) to be low reactivity volatile organic solvents (LR-VOCs) and are EPA-“unlisted” solvents, i.e., their use is largely unrestricted. However, in concentrated form, they are undesirable for many reasons including their unpleasant smell, their excessive volatility and their rapid drying (necessitating application of relatively large quantities of solvent using absorbent cotton balls). Also, their vapors are irritating to the eyes, and they cause desiccation and irritation of the cuticle and skin around the nail. Acetone is also known to cause bronchial irritation and skin erythema via topical exposure. An essentially odor-free liquid nail polish remover having a substantially reduced volatility, based upon the organic solvent gamma butyrolactone is described in Perlman (U.S. Pat. No. 6,521,572).
With the exception of a few LR-VOC solvents such as methyl acetate and acetone that have received exemptions, newly implemented governmental regulations in California require that VOC solvents used in nail polish removers must meet the definition of LVP-VOC solvents, defined as having either a very low vapor pressure (less than 0.1 mm Hg at 20° C.) or a very high boiling point (greater than 216° C.). Unfortunately, most if not all LVP-VOC solvents that are sufficiently active to be useful in nail polish remover formulations, e.g., the alkylene carbonates, are between three and ten times more expensive per pound than acetone. Gamma butyrolactone has neither a sufficiently low vapor pressure nor a sufficiently high boiling point to qualify as an LVP-VOC.
Propylene carbonate-containing nail polish removers and paint strippers have been described previously. Monteleone et al. (U.S. Pat. No. 5,258,070) describe a nail lacquer remover requiring the combination of propylene carbonate, propylene glycol and dimethyl isosorbide. Murase (U.S. Pat. No. 4,801,331) describes a nail lacquer removing composition containing 30%-65% of a carbonate solvent such as propylene carbonate, 10%-50% 1,3-dimethyl-2-imidazolidinone (DMI), 0.2%-20% hydroxypropyl cellulose (thickener) and 13%-40% water. Faryniarz et al. (U.S. Pat. No. 5,486,305) describe a nail polish lacquer remover containing 60%-80% volatile organic solvent (acetone, ethyl acetate and combinations thereof), 3%-20% of a low vapor pressure alkyl or phenyldiester solvent and 5%-20% water. The formulations of Faryniarz et al. may optionally include propylene carbonate (0%-20%), a humectant (0%-20%) and an emollient (0%-10%). In a series of patents, Marquis et al. (U.S. Pat. Nos. 6,040,284, 6,169,061, 6,369,009 and 6,586,380) describe a paint remover containing an alkylene carbonate such as propylene carbonate whose efficacy is enhanced by adding hydrogen peroxide, a strong oxidant. Doscher (U.S. Pat. No. 5,007,969) describes a low toxicity aprotic liquid used for cleaning and for fingernail enamel removal that includes both ethylene diacetate and an alicyclic carbonate solvent that includes propylene and/or ethylene carbonate. Coonan (U.S. Pat. No. 4,594,111) describes a general purpose cleaner-solvent that contains, among other ingredients, from about 50% to about 90% water, from about 5% to about 40% propylene carbonate plus other organic solvents including isopropyl alcohol, diethanolamine (coconut amide) and a tall oil fatty acid. This composition is described as maintaining a pH of 7 and, thus, being non-irritating to normal skin.